1. Field of the Invention
The present invention relates to a marking base composition for displaying (marking) with ink and a marking base using the marking base composition.
2. Description of Related Art
To identify a product, a display such as a product name, a product number, a barcode, and a QR code (registered trademark) (two-dimensional code) is sometimes marked on the product. When the product is marked, from a perspective of ensuring clearer and inerasable marking, widely, a marking base is coated on the surface of the product and a display is shown on this marking base.
As a product using the marking base, there is a catalyst carrier of a honeycomb structure (hereinafter referred to as a “honeycomb catalyst carrier”). The honeycomb catalyst carrier generally displays information such as a product history, a size, and a physical property for the individual products. Furthermore, also in the phase of a honeycomb catalytic body after the process for loading the catalyst, information related to the catalyst might be written on the marking base. For investigation when a trouble occurs on the honeycomb catalyst carrier or the honeycomb catalytic body or investigation when a breakdown occurs on a vehicle and the like on which the honeycomb catalytic body is mounted, these various pieces of information are preferred to be maintained in the state readable even in the process of the usage of this type of vehicle and the like. The methods for marking are roughly divided into a method with ink and a method with laser irradiation.
For marking with ink, a marking base for ink has been proposed. As a representative, a marking base for ink made of a porous resin sheet has been proposed (in Patent Document 1). In this marking base for ink, the porous resin sheet absorbs ink so as to achieve satisfactory adherability of the ink. Additionally, the porous resin sheet promptly absorbs ink so as to reduce accumulation of the ink on the surface of the marking base. As a result, this allows reduction of ink bleed and ink removal when the base surface is rubbed. The marking base for ink is typically made of polymer and thus does not have thermal resistance. In the case where the base is applied to the honeycomb catalyst carrier, the marking base cannot withstand the process for loading the catalyst. Taking into consideration the circumstances, it is possible to apply the marking base made of the porous resin sheet to the honeycomb catalytic body after the catalyst is loaded rather than the honeycomb catalyst carrier before the process for loading the catalyst. However, in the process of the usage of the vehicle, the honeycomb catalytic body is exposed to a high temperature. Therefore, it is difficult to maintain the marked information using the base without thermal resistance.
On the other hand, as the base (the marking base for laser) for display with laser irradiation, a base made of resin, an organic pigment, aluminum hydroxide, and the like has been proposed (in Patent Document 2). In this marking base for laser, the resin is etched by laser irradiation and marking is performed. Furthermore, as the marking base for laser, a marking base made of an inorganic material such as an inorganic pigment and titanium-based ceramic resin (an inorganic marking base for laser) has also been proposed (in Patent Document 3). This inorganic marking base for laser is made of an inorganic material, thus being excellent in thermal resistance and chemical resistance. These marking bases for laser have the advantage that the display is less likely to disappear since the marking base itself is discolored. For example, for the honeycomb catalyst carrier described above, the inorganic marking base for laser excellent in thermal resistance is preferred to be used. This is because using the inorganic marking base for laser allows marking even after the catalyst is loaded. With the inorganic marking base for laser, since the base itself is etched for marking, the display is less likely to disappear even in the case where the base surface is rubbed when the honeycomb catalytic body is mounted on the vehicle to be used.
The marking base for laser has the above-described advantage but does not suit for general use because of necessity of a laser irradiation device. For example, for the honeycomb catalyst carrier, the manufacturer of the honeycomb catalyst carrier is different from the manufacturer that loads the catalyst onto the honeycomb catalyst carrier. In the case where a plurality of manufacturers is involved, not all of the manufacturers can use the laser irradiation device. Thus, the marking base is preferred to have high versatility to allow marking with ink other than the laser irradiation device.
A general marking base for laser is not appropriate for marking with ink. In particular, an inorganic marking base for laser has a dense structure. Accordingly, when marking (for example, ink jet printing) with ink on the marking base for laser is attempted, the ink has difficulty in soaking into the base. Additionally, ink is repelled by the base surface and the ink is not fixed. Furthermore, after heat treatment is performed in the process for loading the catalyst and the like, the surface of the base becomes thermally shrinked. Accordingly, the ink is more likely to be repelled by the base surface. Additionally, performing heat treatment on the inorganic marking base for laser causes formation of cracking in the base due to thermal expansion and contraction. This causes spread of the ink along the cracking, thus causing ink bleed as a result.